To round numbers to the nearest thousand, make the numbers whose last three digits are 001 through 499 into the next lower number that ends in 000. For example, 6424 rounded to the nearest thousand is 6000. Numbers that have the last three digits of 500 or more should be rounded up to the next even thousand. The number 8788 rounded to the nearest thousand is 9000.
So the answer for 12, 345 is 12, 000.
PLEASE MARK BRAINLIEST!!!!!!! Thx